Push technology is a form of data communication where a request for a transaction between a client and a server originates at the server. The technology enables a server to transmit notification messages to client terminals of its own volition. HTTP server push and Java Pushlet are examples of push technology.
The notification messages can be transmitted directly from the server to the client, or the transmission of the notification messages can be mediated by a push notification service.
A push notification service provides a persistent data communication channel to a client endpoint, e.g. an application on a client terminal, for delivering notification messages sent by the server. Push notification services typically require the application to register therewith, which establishes a trust relationship between the push notification service and the application.
In addition to establishing a trusted connection with the application, the push notification service may establish a trusted connection with the device hosting the application. The trusted connection is typically established by validating a pre-provided client certificate, which serves to restrict availability of the push notification services.
Establishment of push notification channel at the push notification service is initiated in response to receipt of a registration request sent by the application: the push notification service associates the push notification channel with the application, and supplies data identifying the push notification channel to the application. In response to receiving the data identifying the channel, the application provides the channel data to the server. The server can then transmit any notification messages along with the channel data to the push notification service for delivery to the application.
The data identifying the channel is created during registration of the application with the push notification service and is valid for the life of the application, as is the trust relationship that is established between the push notification service and the application. Thus, in an arrangement, such as where either the server or the application is compromised, the whole push notification channel will be permanently compromised. This makes the push notification channel unreliable for secured or sensitive communications.